Time-varying relationship between Ukrainian corn and world crude oil prices

Corn belongs to the most important feed and industrial grains in the world being utilized for bioethanol production. Ukraine does not produce biofuels and does not pursue an active renewable energy policy. However, due to significant share of exports, corn prices in Ukraine can be shaped under the influence of biofuel policies pursued by developed countries, as well as under the influence of world energy markets. Therefore, the aim of the paper is to investigate the mechanisms linking Ukrainian export corn prices with Brent oil prices, as well as to quantitatively assess the nature of this relationship. We were especially interested in possible time-varying relationship between the prices. The price analysis was carried out on the basis of monthly data for the period 2001-2020 with the use of rolling correlation technique and rolling causality tests. The results of this research indicate on time-varying co-movements of Ukrainian corn and Brent crude oil prices. The strongest positive correlations and significant bidirectional causality were observed in 2007-2011. However, in most of sub-periods there were no significant relationships between these prices. Among factors strengthening the price linkages are the low corn-oil price ratios, dynamic increase of corn utilized for ethanol production and depletion of the world corn stocks. The conducted analysis confirmed that changes in biofuel demand in other countries can affect Ukrainian corn market due to horizontal integration of grain markets worldwide. Biofuel policy reforms in the EU aiming at decreasing mandatory blending of conventional biofuels in favor of advanced biofuels can lead to decrease in demand for corn in Ukraine after 2021, leading, in turn, to further weakening of linkage between corn and crude oil prices.